/* SPDX-License-Identifier: LGPL-2.1-or-later */

// #include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
// #include <linux/btrfs.h>
// #include <linux/magic.h>
// #include <sys/ioctl.h>
// #include <sys/resource.h>
// #include <sys/stat.h>
// #include <unistd.h>

// #include "alloc-util.h"
// #include "dirent-util.h"
// #include "fd-util.h"
// #include "fileio.h"
// #include "fs-util.h"
// #include "io-util.h"
// #include "macro.h"
// #include "missing_fcntl.h"
// #include "missing_syscall.h"
// #include "parse-util.h"
// #include "path-util.h"
// #include "process-util.h"
#include "socket-util.h"
// #include "sort-util.h"
// #include "stat-util.h"
// #include "stdio-util.h"
// #include "tmpfile-util.h"
// #include "util.h"

/* The maximum number of iterations in the loop to close descriptors in the fallback case
 * when /proc/self/fd/ is inaccessible. */
#define MAX_FD_LOOP_LIMIT (1024*1024)

// int close_nointr(int fd) {
//         assert(fd >= 0);
// 
//         if (close(fd) >= 0)
//                 return 0;
// 
//         /*
//          * Just ignore EINTR; a retry loop is the wrong thing to do on
//          * Linux.
//          *
//          * http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html
//          * https://bugzilla.gnome.org/show_bug.cgi?id=682819
//          * http://utcc.utoronto.ca/~cks/space/blog/unix/CloseEINTR
//          * https://sites.google.com/site/michaelsafyan/software-engineering/checkforeintrwheninvokingclosethinkagain
//          */
//         if (errno == EINTR)
//                 return 0;
// 
//         return -errno;
// }

int safe_close(int fd) {

        /*
         * Like close_nointr() but cannot fail. Guarantees errno is
         * unchanged. Is a NOP with negative fds passed, and returns
         * -1, so that it can be used in this syntax:
         *
         * fd = safe_close(fd);
         */

        // if (fd >= 0) {
        //         PROTECT_ERRNO;

        //         /* The kernel might return pretty much any error code
        //          * via close(), but the fd will be closed anyway. The
        //          * only condition we want to check for here is whether
        //          * the fd was invalid at all... */

        //         // assert_se(close_nointr(fd) != -EBADF);
        // }
        close(fd);

        return -1;
}

// void safe_close_pair(int p[static 2]) {
//         assert(p);
// 
//         if (p[0] == p[1]) {
//                 /* Special case pairs which use the same fd in both
//                  * directions... */
//                 p[0] = p[1] = safe_close(p[0]);
//                 return;
//         }
// 
//         p[0] = safe_close(p[0]);
//         p[1] = safe_close(p[1]);
// }
// 
// void close_many(const int fds[], size_t n_fd) {
//         assert(fds || n_fd <= 0);
// 
//         for (size_t i = 0; i < n_fd; i++)
//                 safe_close(fds[i]);
// }

// int fclose_nointr(FILE *f) {
//         assert(f);
// 
//         /* Same as close_nointr(), but for fclose() */
// 
//         errno = 0; /* Extra safety: if the FILE* object is not encapsulating an fd, it might not set errno
//                     * correctly. Let's hence initialize it to zero first, so that we aren't confused by any
//                     * prior errno here */
//         if (fclose(f) == 0)
//                 return 0;
// 
//         if (errno == EINTR)
//                 return 0;
// 
//         return errno_or_else(EIO);
// }

// FILE* safe_fclose(FILE *f) {
// 
//         /* Same as safe_close(), but for fclose() */
// 
//         if (f) {
//                 PROTECT_ERRNO;
// 
//                 assert_se(fclose_nointr(f) != -EBADF);
//         }
// 
//         return NULL;
// }

// DIR* safe_closedir(DIR *d) {
// 
//         if (d) {
//                 PROTECT_ERRNO;
// 
//                 assert_se(closedir(d) >= 0 || errno != EBADF);
//         }
// 
//         return NULL;
// }

int fd_nonblock(int fd, bool nonblock) {
        int flags, nflags;

        assert(fd >= 0);

        flags = fcntl(fd, F_GETFL, 0);
        if (flags < 0)
                return -errno;

        nflags = UPDATE_FLAG(flags, O_NONBLOCK, nonblock);
        if (nflags == flags)
                return 0;

        if (fcntl(fd, F_SETFL, nflags) < 0)
                return -errno;

        return 0;
}

// int fd_cloexec(int fd, bool cloexec) {
//         int flags, nflags;
// 
//         assert(fd >= 0);
// 
//         flags = fcntl(fd, F_GETFD, 0);
//         if (flags < 0)
//                 return -errno;
// 
//         nflags = UPDATE_FLAG(flags, FD_CLOEXEC, cloexec);
//         if (nflags == flags)
//                 return 0;
// 
//         if (fcntl(fd, F_SETFD, nflags) < 0)
//                 return -errno;
// 
//         return 0;
// }

// _pure_ static bool fd_in_set(int fd, const int fdset[], size_t n_fdset) {
//         assert(n_fdset == 0 || fdset);
// 
//         for (size_t i = 0; i < n_fdset; i++)
//                 if (fdset[i] == fd)
//                         return true;
// 
//         return false;
// }

// static int get_max_fd(void) {
//         struct rlimit rl;
//         rlim_t m;
// 
//         /* Return the highest possible fd, based RLIMIT_NOFILE, but enforcing FD_SETSIZE-1 as lower boundary
//          * and INT_MAX as upper boundary. */
// 
//         if (getrlimit(RLIMIT_NOFILE, &rl) < 0)
//                 return -errno;
// 
//         m = MAX(rl.rlim_cur, rl.rlim_max);
//         if (m < FD_SETSIZE) /* Let's always cover at least 1024 fds */
//                 return FD_SETSIZE-1;
// 
//         if (m == RLIM_INFINITY || m > INT_MAX) /* Saturate on overflow. After all fds are "int", hence can
//                                                 * never be above INT_MAX */
//                 return INT_MAX;
// 
//         return (int) (m - 1);
// }

// int close_all_fds_full(int except[], size_t n_except, bool allow_alloc) {
//         static bool have_close_range = true; /* Assume we live in the future */
//         _cleanup_closedir_ DIR *d = NULL;
//         int r = 0;
// 
//         assert(n_except == 0 || except);
// 
//         if (have_close_range) {
//                 /* In the best case we have close_range() to close all fds between a start and an end fd,
//                  * which we can use on the "inverted" exception array, i.e. all intervals between all
//                  * adjacent pairs from the sorted exception array. This changes loop complexity from O(n)
//                  * where n is number of open fds to O(m⋅log(m)) where m is the number of fds to keep
//                  * open. Given that we assume n ≫ m that's preferable to us. */
// 
//                 if (n_except == 0) {
//                         /* Close everything. Yay! */
// 
//                         if (close_range(3, -1, 0) >= 0)
//                                 return 0;
// 
//                         if (ERRNO_IS_NOT_SUPPORTED(errno) || ERRNO_IS_PRIVILEGE(errno))
//                                 have_close_range = false;
//                         else
//                                 return -errno;
// 
//                 } else {
//                         typesafe_qsort(except, n_except, cmp_int);
// 
//                         for (size_t i = 0; i < n_except; i++) {
//                                 int start = i == 0 ? 2 : MAX(except[i-1], 2); /* The first three fds shall always remain open */
//                                 int end = MAX(except[i], 2);
// 
//                                 assert(end >= start);
// 
//                                 if (end - start <= 1)
//                                         continue;
// 
//                                 /* Close everything between the start and end fds (both of which shall stay open) */
//                                 if (close_range(start + 1, end - 1, 0) < 0) {
//                                         if (ERRNO_IS_NOT_SUPPORTED(errno) || ERRNO_IS_PRIVILEGE(errno))
//                                                 have_close_range = false;
//                                         else
//                                                 return -errno;
//                                         goto opendir_fallback;
//                                 }
//                         }
// 
//                         /* The loop succeeded. Let's now close everything beyond the end */
// 
//                         if (except[n_except-1] >= INT_MAX) /* Don't let the addition below overflow */
//                                 return 0;
// 
//                         int start = MAX(except[n_except-1], 2);
// 
//                         if (close_range(start + 1, -1, 0) >= 0)
//                                 return 0;
// 
//                         if (ERRNO_IS_NOT_SUPPORTED(errno) || ERRNO_IS_PRIVILEGE(errno))
//                                 have_close_range = false;
//                         else
//                                 return -errno;
//                 }
//         }
// 
//         /* Fallback for when close_range() is not supported */
//  opendir_fallback:
//         d = allow_alloc ? opendir("/proc/self/fd") : NULL;
//         if (d) {
//                 struct dirent *de;
// 
//                 FOREACH_DIRENT(de, d, return -errno) {
//                         int fd = -1, q;
// 
//                         if (safe_atoi(de->d_name, &fd) < 0)
//                                 /* Let's better ignore this, just in case */
//                                 continue;
// 
//                         if (fd < 3)
//                                 continue;
// 
//                         if (fd == dirfd(d))
//                                 continue;
// 
//                         if (fd_in_set(fd, except, n_except))
//                                 continue;
// 
//                         q = close_nointr(fd);
//                         if (q < 0 && q != -EBADF && r >= 0) /* Valgrind has its own FD and doesn't want to have it closed */
//                                 r = q;
//                 }
// 
//                 return r;
//         }
// 
//         /* Fallback for when /proc isn't available (for example in chroots) or when we cannot allocate by
//          * brute-forcing through the file descriptor table. */
// 
//         int max_fd = get_max_fd();
//         if (max_fd < 0)
//                 return max_fd;
// 
//         /* Refuse to do the loop over more too many elements. It's better to fail immediately than to
//          * spin the CPU for a long time. */
//         if (max_fd > MAX_FD_LOOP_LIMIT)
//                 return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
//                                        "/proc/self/fd is inaccessible. Refusing to loop over %d potential fds.",
//                                        max_fd);
// 
//         for (int fd = 3; fd >= 0; fd = fd < max_fd ? fd + 1 : -1) {
//                 int q;
// 
//                 if (fd_in_set(fd, except, n_except))
//                         continue;
// 
//                 q = close_nointr(fd);
//                 if (q < 0 && q != -EBADF && r >= 0)
//                         r = q;
//         }
// 
//         return r;
// }

// int same_fd(int a, int b) {
//         struct stat sta, stb;
//         pid_t pid;
//         int r, fa, fb;
// 
//         assert(a >= 0);
//         assert(b >= 0);
// 
//         /* Compares two file descriptors. Note that semantics are
//          * quite different depending on whether we have kcmp() or we
//          * don't. If we have kcmp() this will only return true for
//          * dup()ed file descriptors, but not otherwise. If we don't
//          * have kcmp() this will also return true for two fds of the same
//          * file, created by separate open() calls. Since we use this
//          * call mostly for filtering out duplicates in the fd store
//          * this difference hopefully doesn't matter too much. */
// 
//         if (a == b)
//                 return true;
// 
//         /* Try to use kcmp() if we have it. */
//         pid = getpid_cached();
//         r = kcmp(pid, pid, KCMP_FILE, a, b);
//         if (r == 0)
//                 return true;
//         if (r > 0)
//                 return false;
//         if (!IN_SET(errno, ENOSYS, EACCES, EPERM))
//                 return -errno;
// 
//         /* We don't have kcmp(), use fstat() instead. */
//         if (fstat(a, &sta) < 0)
//                 return -errno;
// 
//         if (fstat(b, &stb) < 0)
//                 return -errno;
// 
//         if ((sta.st_mode & S_IFMT) != (stb.st_mode & S_IFMT))
//                 return false;
// 
//         /* We consider all device fds different, since two device fds
//          * might refer to quite different device contexts even though
//          * they share the same inode and backing dev_t. */
// 
//         if (S_ISCHR(sta.st_mode) || S_ISBLK(sta.st_mode))
//                 return false;
// 
//         if (sta.st_dev != stb.st_dev || sta.st_ino != stb.st_ino)
//                 return false;
// 
//         /* The fds refer to the same inode on disk, let's also check
//          * if they have the same fd flags. This is useful to
//          * distinguish the read and write side of a pipe created with
//          * pipe(). */
//         fa = fcntl(a, F_GETFL);
//         if (fa < 0)
//                 return -errno;
// 
//         fb = fcntl(b, F_GETFL);
//         if (fb < 0)
//                 return -errno;
// 
//         return fa == fb;
// }

// void cmsg_close_all(struct msghdr *mh) {
//         struct cmsghdr *cmsg;
// 
//         assert(mh);
// 
//         CMSG_FOREACH(cmsg, mh)
//                 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
//                         close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int));
// }

// bool fdname_is_valid(const char *s) {
//         const char *p;
// 
//         /* Validates a name for $LISTEN_FDNAMES. We basically allow
//          * everything ASCII that's not a control character. Also, as
//          * special exception the ":" character is not allowed, as we
//          * use that as field separator in $LISTEN_FDNAMES.
//          *
//          * Note that the empty string is explicitly allowed
//          * here. However, we limit the length of the names to 255
//          * characters. */
// 
//         if (!s)
//                 return false;
// 
//         for (p = s; *p; p++) {
//                 if (*p < ' ')
//                         return false;
//                 if (*p >= 127)
//                         return false;
//                 if (*p == ':')
//                         return false;
//         }
// 
//         return p - s <= FDNAME_MAX;
// }

// int fd_get_path(int fd, char **ret) {
//         int r;
// 
//         r = readlink_malloc(FORMAT_PROC_FD_PATH(fd), ret);
//         if (r == -ENOENT) {
//                 /* ENOENT can mean two things: that the fd does not exist or that /proc is not mounted. Let's make
//                  * things debuggable and distinguish the two. */
// 
//                 if (proc_mounted() == 0)
//                         return -ENOSYS;  /* /proc is not available or not set up properly, we're most likely in some chroot
//                                           * environment. */
//                 return -EBADF; /* The directory exists, hence it's the fd that doesn't. */
//         }
// 
//         return r;
// }

// int move_fd(int from, int to, int cloexec) {
//         int r;
// 
//         /* Move fd 'from' to 'to', make sure FD_CLOEXEC remains equal if requested, and release the old fd. If
//          * 'cloexec' is passed as -1, the original FD_CLOEXEC is inherited for the new fd. If it is 0, it is turned
//          * off, if it is > 0 it is turned on. */
// 
//         if (from < 0)
//                 return -EBADF;
//         if (to < 0)
//                 return -EBADF;
// 
//         if (from == to) {
// 
//                 if (cloexec >= 0) {
//                         r = fd_cloexec(to, cloexec);
//                         if (r < 0)
//                                 return r;
//                 }
// 
//                 return to;
//         }
// 
//         if (cloexec < 0) {
//                 int fl;
// 
//                 fl = fcntl(from, F_GETFD, 0);
//                 if (fl < 0)
//                         return -errno;
// 
//                 cloexec = !!(fl & FD_CLOEXEC);
//         }
// 
//         r = dup3(from, to, cloexec ? O_CLOEXEC : 0);
//         if (r < 0)
//                 return -errno;
// 
//         assert(r == to);
// 
//         safe_close(from);
// 
//         return to;
// }

// int fd_move_above_stdio(int fd) {
//         int flags, copy;
//         PROTECT_ERRNO;
// 
//         /* Moves the specified file descriptor if possible out of the range [0…2], i.e. the range of
//          * stdin/stdout/stderr. If it can't be moved outside of this range the original file descriptor is
//          * returned. This call is supposed to be used for long-lasting file descriptors we allocate in our code that
//          * might get loaded into foreign code, and where we want ensure our fds are unlikely used accidentally as
//          * stdin/stdout/stderr of unrelated code.
//          *
//          * Note that this doesn't fix any real bugs, it just makes it less likely that our code will be affected by
//          * buggy code from others that mindlessly invokes 'fprintf(stderr, …' or similar in places where stderr has
//          * been closed before.
//          *
//          * This function is written in a "best-effort" and "least-impact" style. This means whenever we encounter an
//          * error we simply return the original file descriptor, and we do not touch errno. */
// 
//         if (fd < 0 || fd > 2)
//                 return fd;
// 
//         flags = fcntl(fd, F_GETFD, 0);
//         if (flags < 0)
//                 return fd;
// 
//         if (flags & FD_CLOEXEC)
//                 copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
//         else
//                 copy = fcntl(fd, F_DUPFD, 3);
//         if (copy < 0)
//                 return fd;
// 
//         assert(copy > 2);
// 
//         (void) close(fd);
//         return copy;
// }

// int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd) {
// 
//         int fd[3] = { /* Put together an array of fds we work on */
//                 original_input_fd,
//                 original_output_fd,
//                 original_error_fd
//         };
// 
//         int r, i,
//                 null_fd = -1,                /* if we open /dev/null, we store the fd to it here */
//                 copy_fd[3] = { -1, -1, -1 }; /* This contains all fds we duplicate here temporarily, and hence need to close at the end */
//         bool null_readable, null_writable;
// 
//         /* Sets up stdin, stdout, stderr with the three file descriptors passed in. If any of the descriptors is
//          * specified as -1 it will be connected with /dev/null instead. If any of the file descriptors is passed as
//          * itself (e.g. stdin as STDIN_FILENO) it is left unmodified, but the O_CLOEXEC bit is turned off should it be
//          * on.
//          *
//          * Note that if any of the passed file descriptors are > 2 they will be closed — both on success and on
//          * failure! Thus, callers should assume that when this function returns the input fds are invalidated.
//          *
//          * Note that when this function fails stdin/stdout/stderr might remain half set up!
//          *
//          * O_CLOEXEC is turned off for all three file descriptors (which is how it should be for
//          * stdin/stdout/stderr). */
// 
//         null_readable = original_input_fd < 0;
//         null_writable = original_output_fd < 0 || original_error_fd < 0;
// 
//         /* First step, open /dev/null once, if we need it */
//         if (null_readable || null_writable) {
// 
//                 /* Let's open this with O_CLOEXEC first, and convert it to non-O_CLOEXEC when we move the fd to the final position. */
//                 null_fd = open("/dev/null", (null_readable && null_writable ? O_RDWR :
//                                              null_readable ? O_RDONLY : O_WRONLY) | O_CLOEXEC);
//                 if (null_fd < 0) {
//                         r = -errno;
//                         goto finish;
//                 }
// 
//                 /* If this fd is in the 0…2 range, let's move it out of it */
//                 if (null_fd < 3) {
//                         int copy;
// 
//                         copy = fcntl(null_fd, F_DUPFD_CLOEXEC, 3); /* Duplicate this with O_CLOEXEC set */
//                         if (copy < 0) {
//                                 r = -errno;
//                                 goto finish;
//                         }
// 
//                         CLOSE_AND_REPLACE(null_fd, copy);
//                 }
//         }
// 
//         /* Let's assemble fd[] with the fds to install in place of stdin/stdout/stderr */
//         for (i = 0; i < 3; i++) {
// 
//                 if (fd[i] < 0)
//                         fd[i] = null_fd;        /* A negative parameter means: connect this one to /dev/null */
//                 else if (fd[i] != i && fd[i] < 3) {
//                         /* This fd is in the 0…2 territory, but not at its intended place, move it out of there, so that we can work there. */
//                         copy_fd[i] = fcntl(fd[i], F_DUPFD_CLOEXEC, 3); /* Duplicate this with O_CLOEXEC set */
//                         if (copy_fd[i] < 0) {
//                                 r = -errno;
//                                 goto finish;
//                         }
// 
//                         fd[i] = copy_fd[i];
//                 }
//         }
// 
//         /* At this point we now have the fds to use in fd[], and they are all above the stdio range, so that we
//          * have freedom to move them around. If the fds already were at the right places then the specific fds are
//          * -1. Let's now move them to the right places. This is the point of no return. */
//         for (i = 0; i < 3; i++) {
// 
//                 if (fd[i] == i) {
// 
//                         /* fd is already in place, but let's make sure O_CLOEXEC is off */
//                         r = fd_cloexec(i, false);
//                         if (r < 0)
//                                 goto finish;
// 
//                 } else {
//                         assert(fd[i] > 2);
// 
//                         if (dup2(fd[i], i) < 0) { /* Turns off O_CLOEXEC on the new fd. */
//                                 r = -errno;
//                                 goto finish;
//                         }
//                 }
//         }
// 
//         r = 0;
// 
// finish:
//         /* Close the original fds, but only if they were outside of the stdio range. Also, properly check for the same
//          * fd passed in multiple times. */
//         safe_close_above_stdio(original_input_fd);
//         if (original_output_fd != original_input_fd)
//                 safe_close_above_stdio(original_output_fd);
//         if (original_error_fd != original_input_fd && original_error_fd != original_output_fd)
//                 safe_close_above_stdio(original_error_fd);
// 
//         /* Close the copies we moved > 2 */
//         for (i = 0; i < 3; i++)
//                 safe_close(copy_fd[i]);
// 
//         /* Close our null fd, if it's > 2 */
//         safe_close_above_stdio(null_fd);
// 
//         return r;
// }

// int fd_reopen(int fd, int flags) {
//         int new_fd;
// 
//         /* Reopens the specified fd with new flags. This is useful for convert an O_PATH fd into a regular one, or to
//          * turn O_RDWR fds into O_RDONLY fds.
//          *
//          * This doesn't work on sockets (since they cannot be open()ed, ever).
//          *
//          * This implicitly resets the file read index to 0. */
// 
//         new_fd = open(FORMAT_PROC_FD_PATH(fd), flags);
//         if (new_fd < 0) {
//                 if (errno != ENOENT)
//                         return -errno;
// 
//                 if (proc_mounted() == 0)
//                         return -ENOSYS; /* if we have no /proc/, the concept is not implementable */
// 
//                 return -ENOENT;
//         }
// 
//         return new_fd;
// }

// int read_nr_open(void) {
//         _cleanup_free_ char *nr_open = NULL;
//         int r;
// 
//         /* Returns the kernel's current fd limit, either by reading it of /proc/sys if that works, or using the
//          * hard-coded default compiled-in value of current kernels (1M) if not. This call will never fail. */
// 
//         r = read_one_line_file("/proc/sys/fs/nr_open", &nr_open);
//         if (r < 0)
//                 log_debug_errno(r, "Failed to read /proc/sys/fs/nr_open, ignoring: %m");
//         else {
//                 int v;
// 
//                 r = safe_atoi(nr_open, &v);
//                 if (r < 0)
//                         log_debug_errno(r, "Failed to parse /proc/sys/fs/nr_open value '%s', ignoring: %m", nr_open);
//                 else
//                         return v;
//         }
// 
//         /* If we fail, fall back to the hard-coded kernel limit of 1024 * 1024. */
//         return 1024 * 1024;
// }

/* This is here because it's fd-related and is called from sd-journal code. Other btrfs-related utilities are
 * in src/shared, but libsystemd must not link to libsystemd-shared, see docs/ARCHITECTURE.md. */
// int btrfs_defrag_fd(int fd) {
//         int r;
// 
//         assert(fd >= 0);
// 
//         r = fd_verify_regular(fd);
//         if (r < 0)
//                 return r;
// 
//         if (ioctl(fd, BTRFS_IOC_DEFRAG, NULL) < 0)
//                 return -errno;
// 
//         return 0;
// }
